Quick answer
More than about 5mm a day in a Johannesburg summer is more than evaporation and suggests a leak — usually a cracked skimmer throat, a failed return fitting seal, or a buried suction or return pipe. The bucket test separates evaporation from leakage definitively: float a bucket of pool water on a step and compare the drop inside and outside over forty-eight hours.
Common causes
- Cracked skimmer throat, the single most common pool leak
- Failed seal on a weir or return fitting
- Buried suction or return pipe cracked underground
- Perished seals at the pump or filter losing water while running
- Cracked pool shell or failed expansion joint on an older pool
- Backwashing more often than you think, which is loss rather than leakage
What you can do now
- 1Run the bucket test for forty-eight hours and compare the two levels
- 2Mark the water level and check whether it stops dropping at a particular fitting height
- 3Test with the pump on and then off for equal periods — a faster drop with the pump running points at the pressure side
- 4Inspect around the pump and filter for damp ground while running
- 5Note how much you top up per week so the loss can be quantified
When to call a professional
If the pool drops faster than the bucket, book pool leak detection. Pressure testing the suction and return lines separately identifies whether the loss is a fitting or a buried pipe, which is the difference between a seal replacement and excavation. Bring your bucket-test figures — they save the technician a day of establishing what you already know.
Typical cost in Johannesburg
Pool leak detection R1,200–R2,400
Indicative ranges only. We provide written, itemised quotes before any work.
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